In this lesson, we treat the most subtle and delicate movement of a tennis stroke. We use the forehand as our illustration, but this applies to every stroke.

Extend the shoulder to keep the racquet from moving in a circle. Click image to see video.

As the racquet moves from the rotation into the acceleration stage, the rotation of the upper arm takes over from the hips and legs to provide the final burst of acceleration. Because of the way the arm is hinged to the body, the racquet can be accidentally pulled into a circular motion at the last minute unless the shoulder and elbow are slightly extended outward to maintain a straight-line movement of the racquet face into the ball. The arrow in the video points to the movement in question. Note how the shoulder and elbow extending outward from the body keep the racquet moving in the correct direction.

This movement is the most subtle movement in a stroke and can only be seen clearly in slow-motion photography of at least 500 frames per second.